Body-worn thermometry solutions

ABSTRACT

An example system includes a patch defining a first surface and a second surface opposite the first surface. The first surface is removably attachable to skin of a subject. The patch includes a conductor associated with the first surface, a first sensor configured to determine a temperature of the conductor, and a second sensor configured to determine an additional temperature. The first sensor is separated from the second sensor by material having a known thermal resistance. The patch also includes a transmitter operably connected to the first and second sensors.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None

REFERENCE TO A “SEQUENCE LISTING”

Not applicable

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure generally relates to devices and methods fortemperature determination and, in particular, to devices and methods fordetermining a core temperature, such as a sub-skull temperature, of asubject.

Description of Related Art

Internal body temperature is widely used by physicians and otherhealthcare professionals as an indicator of a person's health. In mosthealthcare facilities, various non-invasive techniques may be utilizedto measure internal temperature before, during, and/or after treatment.Such techniques typically include the use of oral, rectal, tympanic, oraxial thermometers. These instruments are useful in providing asubstantially instantaneous temperature reading, but are not generallyused to provide relatively long-term monitoring of a patient'stemperature. However, such long-term temperature monitoring can beuseful to healthcare professionals when providing treatment. Suchdevices are not well-suited for these types of temperature measurementssince, for example, disposing a thermometer in the mouth of a patientfor long periods of time can cause discomfort and can be otherwisecumbersome. Moreover, often the condition of the patient may make itdifficult or impossible to access, for example, the mouth, rectum,and/or other areas of the body where temperature is typically measuredwith such devices.

To overcome some of these problems, devices have been developed enablingcontinuous monitoring of patient temperature. Such devices are typicallyin the form of an adhesive patch or bandage-like structure having one ormore temperature sensors. Such devices are typically adhered to thepatient's skin overlaying a portion of the temporal artery. Thesedevices, however, are characterized by deficiencies making themundesirable for use in many patient treatment settings. For example,such devices must be placed in close proximity to the temporal artery inorder to obtain an accurate temperature measurement. However, since thetemporal artery is beneath the skin, and is not easily visible, suchdevices are often mispositioned on the patient. Such mispositioning canhave adverse affects on the accuracy of the temperature measurementobtained using such devices. In addition, the temperature at the skinsurface can be significantly influenced by the ambient temperature andoften does not correlate well with core body temperature. Moreover,ambient conditions can often degrade the accuracy of temperaturemeasurements made by such devices.

The example embodiments of the present disclosure overcome one or moreof the deficiencies described above.

BRIEF SUMMARY OF THE INVENTION

In an example embodiment of the present disclosure, a system includes apatch defining a first surface and a second surface opposite the firstsurface, wherein the first surface is removably attachable to skin of asubject. In such a system, the patch includes a conductor associatedwith the first surface, a first sensor configured to determine atemperature of the conductor, and a second sensor configured todetermine an additional temperature, wherein the first sensor isseparated from the second sensor by material having a known thermalresistance. The patch also includes a radio-frequency identification“RFID”) antenna operably connected to the first and second sensors. TheRFID antenna may be configured to provide power to the first and secondsensors, and to provide at least one of the first temperature, theadditional temperature, or a core temperature of the subject to an RFIDreader. As used in this specification, RFID refers to any system wherebyenergy from a remote device is used in whole, or in part to power thetemperature circuit and/or to create a data transmission. Datatransmission may be through an active radio frequency (“RE”) transmitteror through modulation of the load on the received, powering signal, orany other method of modulating a signal onto a carrier. Standards suchas near-field communication (“NEC”) are included within this definitionas would be a Bluetooth beacon that is powered in whole or in part bythe remote device. The RFID antenna may have various forms including,but not limited to electric antennas, magnetic antennas, dipoles, coils,loops, monopoles, microstrips, printed circuit board antennas, and thelike.

In another example embodiment of the present disclosure, a systemincludes a patch defining a first surface and a second surface oppositethe first surface, wherein the first surface is removably attachable toskin of a subject. In such a system, the patch includes a conductorassociated with the first surface, a first thermistor configured todetermine a temperature of the conductor, and a second thermistorconfigured to determine an additional temperature, wherein the firstthermistor is separated from the second thermistor by a portion of thepatch having a known thermal resistance. Such a patch also includes awireless transmitter operably connected to the first and secondthermistors, wherein the transmitter is configured to wirelessly provideat least one of the first temperature, the additional temperature, or acore temperature of the subject to a device separate from the patch.Alternately, the system might transmit the directly measured parameteror parameters of the temperature sensor, for example the resistance of athermistor, the resistance of a thermocouple, or the forward voltage ofa diode. Transmitting the directly measured parameter or parameters ofthe temperature sensor is considered the same as transmitting thetemperature since there is a 1:1 relationship between the directlymeasured parameter and the temperature. For example, if using athermistor, the direct measure is the resistance and the Steinhart-Hartequation may be used to calculate the temperature, and this calculationmay be done by the patch 10 or the receiver, or some computing componentupstream from the server. In this specification, the term transmitting atemperature includes transmitting the directly measured parameter ortransmitting the specific temperature calculated from the directlymeasured parameter. Alternately, a neural network or other machinelearning algorithm may be used to determine the temperature. Forexample, and assuming thermistors are used to detect the temperature, byplacing the patch on a patient, recording the resistances of the variousthermistors and the core temperature (measured for example using a Foleycatheter), a neural network may be trained to determine the coretemperature using methods familiar to those well versed in the art.

In still another example embodiment of the present disclosure, a methodof manufacturing a system includes providing a patch defining a firstsurface and a second surface opposite the first surface, wherein thefirst surface is removably attachable to skin of a subject. The methodalso includes connecting a conductor to the patch at a location spacedfrom the second surface, and operably connecting a first sensor to thepatch, the first sensor being configured to determine a temperature ofthe conductor. The method further includes operably connecting a secondsensor to the patch, the second sensor being spaced from the firstsensor by a portion of the patch having a known thermal resistance, thesecond sensor being configured to determine an additional temperature.The method also includes connecting a wireless transmitter to the patch,the wireless transmitter being operably connected to the first andsecond sensors, and being configured to wirelessly provide at least oneof the first temperature, the additional temperature, or a coretemperature of the subject to a device separate from the patch.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 illustrates a patch positioned on a forehead of a subjectaccording to an example embodiment of the present disclosure.

FIG. 2 illustrates a patch according to an example embodiment of thepresent disclosure.

FIG. 3 provides a schematic illustration of a patch, according to anexample embodiment of the present disclosure.

FIG. 4 illustrates a first surface of a patch according to an exampleembodiment of the present disclosure.

FIG. 5 illustrates a temperature plot according to an example embodimentof the present disclosure.

FIG. 6 illustrates a temperature plot according to another exampleembodiment of the present disclosure.

FIG. 7 illustrates a partial cross-section of a forehead of a subjectwith a patch connected thereto, according to another example embodimentof the present disclosure.

FIG. 8 provides a flowchart illustrating an example method of thepresent disclosure.

FIG. 9 provides a flowchart illustrating another example method of thepresent disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The various figures described herein illustrate example temperaturemeasurement systems, devices, and/or patches 10 useful in determiningthe temperature of a subject 14. These figures also illustratetemperature plots and methods associated with such systems. As describedherein, and as shown in FIG. 1, a “subject” 14 may be, for example, ahuman being in need of medical treatment or diagnosis. In suchembodiments, a patch 10 of the present disclosure may be connected,affixed, disposed, adhered, and/or otherwise connected to a forehead 12of the subject 14. For example, the patch 10 may be temporarily and/orremovably connected to and/or may temporarily contact at least a portionof the forehead 12 during use. Positioning the patch 10 on the forehead12 of the subject 14 may be advantageous when determining a temperatureof the subject 14 since the forehead 12 is relatively isolated fromveins, arteries, and/or other blood flow passages. The flow of bloodthrough such anatomical structures may cause error in temperaturemeasurements that are taken using the patch 10 or other nonintrusivedevices. Such errors may, in turn, affect the accuracy of a coretemperature of the subject 14 that is calculated and/or otherwisedetermined based at least partly on such temperature measurements.

The core temperatures of the subject 14 described herein may be, forexample, a sub-skull temperature and/or any other like internal bodytemperature of the subject 14. For example, the core temperature maycomprise the internal temperature of the subject 14 distal to thefrontal portion of the skull. As referred to herein, the forehead 12 maycomprise the frontal skull bone 52 and the layer of skin 54 positionedproximal and/or overlaying the skull bone 52 (FIG. 7). In furtherexamples, other body positions and/or measurement sites may be used,such as above the sternum, or directly above an artery.

As shown in at least FIG. 2, the patch 10 may define at least twosurfaces and, in an example embodiment, the patch 10 may define a firstsurface 16 configured to at least temporarily contact and/or beremovably attached to the forehead 12 of the subject 14. The patch 10may also include a second surface 18 disposed opposite the first surface16 and configured to be exposed to ambient conditions such as, forexample, to ambient air or other like environments in a hospital and/orother healthcare facility.

As shown in FIGS. 2 and 3, the patch 10 may include one or morecomponents configured to assist in calculating a sub-skull temperatureand/or other core temperature based on a measurement of heat flow. Forexample, the patch 10 may include one or more operator interfaces 20.Such operator interfaces 20 may include one or more buttons, switches,keypads, dials, knobs, and/or other like devices configured to assist incontrolling one or more functions of the patch 10. Such operatorinterfaces 20 may be useful in, for example, energizing and/ordeenergizing one or more components of the patch 10, toggling throughand/or selecting one or more modes of operation or display, enablingand/or disabling one or more alarms or signals associated with patchoperation, initiating a single instantaneous sub-skull temperaturecalculation, initiating a substantially continuous and/or repeatingsub-skull temperature calculation, and/or other like modes, functions,or operations.

In an example embodiment, the patch 10 may include one or morecontrollers 21, and each of the operator interfaces 20 may befunctionally, operably, electrically, and/or otherwise connected to thecontroller 21. At least one of the additional components of the patch 10may also be similarly connected to the controller 21, and the controller21 may be configured to control the operation of each such component. Inan example embodiment, the controller 21 may be configured to receivesignals, information, measurements, and/or other data from one or moresensors of the patch 10, and to calculate a sub-skull temperature and/orother core temperature of the subject 14 based on the informationreceived. The controller 21 may also be configured to execute one ormore commands and/or control programs. For example, the controller 21may be programmed to initiate one or more alarms in response tocalculating a sub-skull temperature and/or other core temperature thatis greater than or equal to a predetermined threshold temperature. Inaddition, the controller 21 may be configured to initiate such an alarmduring a substantially continuous sub-skull temperature and/or othercore temperature calculation operation if the calculated temperatureincreases and/or decreases at a rate that is greater than or equal to apredetermined threshold temperature change rate. The controller 21 mayalso initiate such an alarm to indicate that a location of the patch 10should be changed, and such a location change alarm may be initiated inresponse to one or more sensed metrics indicative of blood flow at theforehead skin 54.

In an example embodiment, the patch 10 may also include one or moredisplays 22. The display 22 may be, for example, a liquid crystal diode(LCD) screen, a light emitting diode (LED) display, a digital read-out,a touchscreen, and/or any other like display device. The display 22 maybe configured to, for example, indicate the calculated sub-skulltemperature of the subject 14 during operation of the patch 10. Thedisplay 22 may be configured to display the calculated sub-skulltemperature and/or other core temperature substantially instantaneouslyand/or substantially continuously depending on the mode of operation ofthe patch 10. The display 22 may also be configured to indicate the modeof operation of the patch 10 (for example, continuous or instantaneousmodes of temperature calculation), as well as whether one or morethreshold temperatures, threshold temperature change rates, and/orsensed blood flow metric thresholds have been met or exceeded. As shownin FIGS. 1 and 2, the display 22 may be, for example, a substantiallynumerical digital display, and may also be configured to display anyother typical operating information such as, for example, text, atemperature vs. time graph, or other information. In some embodiments,one or more components of the patch 10 described herein, such as thedisplay 22 or the operator interfaces 20 may be omitted.

The patch 10 may also include at least one sensor. For example, thepatch 10 may include a first sensor 24 disposed at or proximate thefirst surface 16. In an example embodiment, the sensor 24 may beembedded within the patch 10 so as to be integral with the patch 10.Alternatively, the sensor 24 may be substantially internal to the patch10 such that the sensor 24 may be positioned and/or otherwise configuredto sense a characteristic of the first surface 16 and/or acharacteristic of a portion or component of the patch 10 associated withthe first surface 16. For example, the sensor 24 may be positionedand/or otherwise configured to sense a temperature of the first surface16 of the patch 10 while the first surface 16 is in contact with and/orattached to the forehead 12. Such a sensor 24 may comprise, for example,a thermocouple, a thermistor, a thermometer, a resistance temperaturedetector (RTD), diode, and/or any other like device useful in measuringtemperature. In additional example embodiments, such a sensor 24 maycomprise any temperature-sensitive material or coating known in the art.

In an example embodiment, the sensor 24 may be substantially exposed toand/or disposed in contact with the skin 54 of the forehead 12 while thefirst surface 16 of the patch 10 is in contact with the forehead 12.Alternatively, the first surface 16 may include a relatively thin layer,wall, film, and/or other like barrier extending between the skin 54 andthe sensor 24 while the first surface 16 is in contact with the forehead12. Such a barrier may form at least a portion of the first surface 16.In such an example embodiment, the thermal resistance of such a barriermay be substantially negligible so as to maximize the accuracy of theone or more measurements made by the sensor 24. Alternatively, thethermal resistance of the barrier may be known or empiricallydetermined, and this thermal resistance may be taken into account whencalculating the sub-skull temperature and/or other core temperature ofthe subject 14.

In example embodiments in which the patch 10 includes such a barrier,the sensor 24 may be configured to sense, measure, and/or otherwisedetect one or more properties, conditions, and/or characteristics of thebarrier. As will be described in greater detail below, in someembodiments the patch 10 may also include a conductor associated withthe first surface 16. In such embodiments, the first sensor 24 may beconfigured to determine a temperature and/or other characteristics ofthe conductor. Additionally, in some embodiments in which the patch 10includes a conductor, the barrier described above may at least partiallyoverlay the conductor, or the barrier may be omitted.

The patch 10 may also include at least one additional sensor, such as asecond sensor 26. In some example embodiments, the second sensor 26 maybe substantially identical to the first sensor 24. As shown in, forexample, FIGS. 2 and 3, the sensor 26 may be disposed at and/orproximate to the second surface 18. In an example embodiment, the sensor26 may be exposed to ambient conditions, while in additional exampleembodiments, the second surface 18 may include a layer, wall, film,and/or barrier (not shown) similar to that described above with regardto the first surface 16. In such an example embodiment, the barrier mayextend between the sensor 26 and the ambient environment to protect thesensor 26 from contaminants, wet conditions, and/or other potentiallydamaging or harmful environmental elements. Similar to the barrierdiscussed above with regard to the first surface 16, a like barrier mayform at least a portion of the second surface 18 and may have asubstantially negligible thermal resistance so as not to hinder theaccuracy of measurements obtained by the sensor 26. Alternatively, thethermal resistance of such a barrier may be taken into account whencalculating the sub-skull temperature.

Although shown in FIGS. 2 and 3 as including two sensors 24, 26, inadditional example embodiments, the patch 10 may include any number ofadditional sensors (not shown) configured to assist in sensingconditions of the subject 14 and/or the patch 10 such as temperature,blood pressure, pulse oximetry, heart rate, and/or other like metrics.Such additional sensors may be disposed at or along any of the surfaces16, 18 of the patch 10 and/or at any other useful position along and/orwithin the patch 10. For example, the patch 10 may also include a thirdsurface 28 that extends substantially perpendicular to the first surface16. The patch 10 may also include a fourth surface 30 opposite the thirdsurface 28. In such embodiments, the patch 10 may have a thickness Aextending from the first surface 16 to the second surface 18, and aheight F (FIG. 3) extending from the third surface 28 to the fourthsurface 30. In such examples, one or more additional sensors may bedisposed at, along, and/or proximate the third surface 28 or the fourthsurface 30.

The patch 10 may be made from any substantially rigid medically approvedmaterial known in the art. Such materials may include, for example,plastics, rubber, polymers, synthetic materials, cloth, mesh, and/orcombinations thereof. For example, the patch 10 may be made frommaterials similar to removable bandages or other like materials. Thesematerials may allow for breathability during use and for easy disposalonce use is complete. In addition, such patch materials may besubstantially flexible, substantially light-weight, and/or relativelycomfortable such that a patch 10 may be disposed on and/or removablyattached to the forehead 12 of a subject 14 for extended periods oftime. To assist with such removable connection, any known adhesive maybe disposed on at least a portion of the first surface 16.Alternatively, one or more elastic straps, headbands, belts, ties, orthe like may be connected to at least a portion of the patch 10 toassist in removably attaching the patch 10 to the forehead 12.

The patch 10 may have a known thermal resistance, and such thermalresistance may depend upon, for example, the thickness A of the patch 10as well as the one or more materials utilized to form the patch 10. Thethermal resistance of the plastics, rubber, polymers, or other materialsused to form the patch 10 may be known in the art, and the sub-skulltemperature and/or other core temperature determined in accordance withone or more of the example methods described herein may be calculatedbased upon the thermal resistance of at least a portion of the patch 10.For example, as shown in FIG. 3, the first sensor 24 may be separatedfrom the second sensor 26 by material 46 having a known thermalresistance. In such embodiments, the material 46 may be the materialused to form the patch 10. In other embodiments, however, the material46 may comprise an additional piece of plastic, rubber, polymer, orother material, having a known thermal resistance, embedded within thepatch 10. In any of the embodiments described herein, a core temperatureof the subject 14 may be determined based at least partly on thetemperatures measured by the first and second sensors 24, 26, and thethermal resistance of the material 46. In such embodiments, the coretemperature of the subject 14 may also be determined based at leastpartly on the distance by which the first sensor 24 is spaced from thesecond sensor 26. In such examples, this distance may comprise athickness G and/or other dimension of the material 46 spacing the firstsensor 24 from the second sensor 26.

Moreover, example patches 10 of the present disclosure may be made frommore than one material, and each portion of the patch 10 may have aunique thermal resistance depending upon the materials utilized to formthe particular portion of the patch 10 and/or the relative thickness ofthe portion. For example, the material 46 separating the first andsecond sensors 24, 26 may be made from a first material, and theremainder of the patch 10 (or at least a second portion of the patch 10)may be made from a second material different than the first material. Insuch an example embodiment, the different portions of the patch 10 mayhave unique different thermal resistances. The different thermalresistances of each portion of the patch 10 may be taken into accountwhen calculating, for example, the core temperature of the subject 14.

With continued reference to FIG. 3, in some examples the patch 10 mayfurther include one or more wireless transmitters 32. Such transmitters32 may comprise, for example, one or more transponders, transceivers,radio-frequency identification (RFID) coils, and/or other componentsconfigured to receive signals, power, and/or information from a remotesource, such as a remote controller, a hand-held reader, or other suchdevice. Such transmitters 32 may also comprise one or more devicesconfigured to transmit signals, data, and/or other information to remotereceivers. For example, a transmitter 32 of the patch 10 may beconfigured to wirelessly transmit information corresponding to one ormore sensed temperatures to a remote computer, controller, reader, orother device utilized in the calculation of sub-skull temperaturesand/or other core temperatures of the subject 14. An example remotedevice 58 is illustrated in FIG. 7. Such example transmitters 32 mayfacilitate communication with remote readers or other remote devices 58using, for example, radio, infrared, wireless, WI-FI®, BLUETOOTH®,and/or other like technologies. Accordingly, such a transmitter 32 mayenable noncontact monitoring of subjects 14 fitted with the patch 10, inrelatively close proximity (e.g., within a hospital examination roomand/or within a distance of several feet). Such a transmitter 32 mayalso enable monitoring of subjects 14 fitted with the patch 10 from oneor more remote locations within, for example, a hospital or otherhealthcare facility. In addition, such a transmitter 32 may facilitate awireless network connection with one or more routers, servers, or thelike.

In such an example embodiment, the transmitter 32 may enable ahealthcare professional to monitor one or more conditions of the subject14 remotely via a data and/or internet connection or the like. Althoughnot shown in FIGS. 2 and 3, it is understood that such a patch 10 mayalso include one or more USB ports, communication terminals, or otherlike components configured to facilitate connecting the patch 10 to oneor more computers, controllers, monitors, servers, routers, or otherlike monitoring devices via one or more cables, wires, leads, or otherlike connection devices.

In example embodiments, the transmitter 32 may comprise a component of acontrol circuit within the patch 10. For example, the transmitter 32 maybe electrically, operably, and/or otherwise connected to the controller21 via one or more switches 34. Additionally, the transmitter 32 may beelectrically, operably, and/or otherwise connected to the first andsecond sensors 24, 26 via the switch 34 and/or via the controller 21.Via such connections, the transmitter 32 may be configured to providepower to and/or otherwise activate the first sensor 24 and/or the secondsensor 26 during operation of the patch 10.

For example, in embodiments in which the transmitter 32 comprises anRFID coil, the transmitter 32 may be energized by passing an RFID readeror other such device 58 in close proximity thereto. Upon beingenergized, the transmitter 32 may direct power to at least one of thefirst and second sensors 24, 26, via the controller 21, therebyactivating the at least one of the first and second sensors 24, 26. Inresponse to such activation, the at least one of the first and secondsensors 24, 26 may sense, detect, and/or otherwise determine arespective temperature, and may direct one or more signals to thetransmitter 32 indicative of such temperature. In an example embodiment,such signals may be directed to the transmitter 32 via the controller21, and the transmitter 32 may direct such signals to the RFID reader orother device 58. Alternatively, such signals may be directed from the atleast one of the first and second sensors 24, 26 to the controller 21.At least partly in response to receiving such signals, the controller 21may determine, among other things, a core temperature of the subject 14based at least partly on the temperatures determined by the at least oneof the first and second sensors 24, 26. The controller 21 may thendirect a signal indicative of the determined core temperature to thetransmitter 32, and the transmitter 32 may provide a signal to the RFIDreader or other device 58 indicative of the determined core temperature.In still further example embodiments, the circuit described above mayinclude one or more modulators, filters, amplifiers, signalconditioners, and/or other circuit components (not shown). Suchcomponents may assist in, among other things, providing information fromthe first and second sensors 24, 26 to the controller 21 and/or to thetransmitter 32.

As noted above, in example embodiments the patch 10 may include aconductor 36 associated with the first surface 16. In such embodiments,the first sensor 24 may be configured to determine a temperature and/orother characteristics of the conductor 36. As shown in FIG. 3, theconductor 36 may comprise a front surface 38 disposed substantiallyparallel to the second surface 18 of the patch 10. The conductor 36 mayalso include a top surface 40 disposed substantially perpendicular tothe front surface 38, and a bottom surface 42 opposite the top surface40. The conductor 36 may further include a back surface 44 opposite thefront surface 38. In any of the example embodiments described herein,the conductor 36 may comprise a substantially planar sheet of conductivematerial such as copper, gold, and/or any other metal or alloy. In stillfurther embodiments, the conductor may comprise a conductive liquid orgel disposed within and/or contained by the patch 10. In any of theexamples described herein, the patch 10 may define one or more cavities,and the conductor 36 may be at least partially disposed in one or moresuch cavities.

In some examples, at least part of the conductor 36 may extendsubstantially coplanar with the first surface 16 of the patch 10. Insuch examples, at least part of the conductor 36, such as at least partof the front surface 38 may form at least part of the first surface 16of the patch 10. As noted above, the patch 10 may also include one ormore additional barriers or other components overlaying at least aportion of the conductor 36 so as to protect the conductor 36 fromcontamination caused by contact between the conductor 36 and the skinand/or other body surface of the subject 14. Alternatively, as shown inFIG. 3 at least part of the conductor 36, such as the front surface 38,may be spaced from the first surface 16 of the patch 10 by a distance B.For example, the conductor 36 may be embedded substantially within thepatch 10, and a portion of the patch material may space the frontsurface 38 of the conductor 36 from the first surface 16 of the patch 10by the distance B.

As shown in FIG. 3, the front surface 38 of an example conductor 36 maybe spaced from the back surface 44 of the conductor 36 by a thickness Cof the conductor extending from the front surface 38 to the back surface44. In some examples, it may be desirable to minimize the thickness C ofthe conductor 36 in order to assist in maximizing heat transfer betweenthe skin surface on which the patch 10 is disposed and the conductor 36.In some examples, the thickness C may be between approximately 0.001 mmand approximately 5 mm. Additionally, the top surface 40 of theconductor 36 may be spaced from the bottom surface 42 of the conductor36 by a height D of the conductor 36 extending from the top surface 40to the bottom surface 42.

Regardless of the particular configuration of the conductor 36, theconductor 36 may be positioned at any location relative to, for example,the first surface 16, third surface 28, and/or fourth surface 30 of thepatch 10 to maximize the usefulness of the temperature determinationmade by, for example, the first sensor 24. For example, minimizing thedistance B by which the front surface 38 of the conductor 36 is spacedfrom the first surface 16 of the patch 10 may improve the correlationbetween the temperature of the conductor 36 sensed by the first sensor24 and the actual temperature of the skin surface on which the patch 10is disposed. Improving this correlation may improve the accuracy of thesub-skull and/or other core temperature determinations made using thepatch 10.

Additionally, in some example embodiments it may be desirable tomaximize the height D of the conductor 36 in order to maximize thesurface area of the conductor 36 available for interaction with the skinsurface on which the patch 10 is disposed. By maximizing the surfacearea, for example, inaccuracies in skin temperature measurement causedby skin irregularities, air pockets formed between the skin surface andthe first surface 16 of the patch 10, and/or other environmental factorsassociated with skin temperature measurement can be mitigated. In suchexamples, the first sensor 24 may comprise one or more temperaturesensing elements configured to determine multiple respectivetemperatures of the conductor 36. The thermal conductivity of layer 36improves the conduction of heat from the skin surface to the firsttemperature sensor 24 and provides a small thermal mass that creates alow-pass filter on small perturbations, for example, if the sensorposition changes slightly. In some embodiments, such sensing elementsmay be configured to determine the respective temperatures of the frontsurface 38 of the conductor 36. In such examples, the controller 21, thesensor 24, and/or other components of the various systems describedherein may determine the temperature of the conductor 36 by averagingand/or otherwise processing each of the temperatures determined by themultiple sensing elements of the first sensor 24. Such processing mayassist in mitigating the inaccuracies in skin temperature measurementdescribed above.

Further, since portions of the patch 10, such as the third surface 28and/or the fourth surface 30 can be susceptible to variations intemperature caused by ambient conditions, it may also be desirable tospace at least a portion of the conductor 36 from such portions of thepatch 10. Such spacing may be achieved by, for example, modifying theheight D of the conductor 36 and/or by modifying the height F of thepatch 10. As shown in FIG. 3, the top surface 40 of the conductor 36 maybe spaced from the third surface 28 by a first distance E₁, and thebottom surface 42 of the conductor 36 may be spaced from the fourthsurface 30 of the patch 10 by a second distance E₂ substantially equalto the first distance E₁. Spacing, for example, the top and bottomsurfaces 40, 42 of the conductor 36 from the third and fourth surfaces28, 30 of the patch 10 in this way may assist in minimizing inaccuraciesin skin temperature measurement caused by at least one of the third andfourth surfaces 28, 30 having a temperature that is greater than or lessthan the actual temperature of the skin surface on which the patch 10 isdisposed.

Collectively, the first and second distances E₁, E₂ may be referred toas a “pullback” of the patch 10, and in general, such a pullback may bedefined by the distance by which one or more surfaces or edges of theconductor 36 is spaced from one or more corresponding adjacent surfacesor edges of the patch 10. It is understood that by increasing thepullback of the patch 10, inaccuracies in skin temperature measurementcaused by, for example, the relative coolness of the third and fourthsurfaces 28, 30 of the patch 10 may be minimized. However, increasingthe first and second distances E₁, E₂ may also decrease the overallheight D of the conductor 36, and may result in an overall decrease inthe surface area of the front surface 38. Accordingly, in some examples,increasing the pullback of the patch 10 may result in a patch 10 that ismore susceptible to inaccuracies in skin temperature measurement causedby skin irregularities, air pockets formed between the skin surface andthe first surface 16 of the patch 10, and/or other environmental factorsassociated with skin temperature measurement.

As noted above, the second sensor 26 may be configured to determine atleast one additional temperature associated with the patch 10. In someexamples, such an additional temperature may comprise a temperature ofat least a portion of the patch 10 spaced from the first surface 16. Inexample embodiments, such an additional temperature may comprise atemperature of and/or otherwise associated with the second surface 18.Additionally, in some example embodiments such an additional temperaturemay comprise an ambient temperature associated with the environment inwhich the patch 10 is used. In embodiments in which the additionaltemperature determined by the second sensor 26 comprises an ambienttemperature and/or a temperature of and/or otherwise associated with thesecond surface 18, the second sensor 26 may be disposed proximate,adjacent to, at, and/or on the second surface 18 of the patch 10 inorder to minimize and/or eliminate inaccuracies in such temperaturemeasurements caused by, for example, the temperature of the patch 10itself. On the other hand, in embodiments in which the additionaltemperature determined by the second sensor 26 comprises a temperatureof at least a portion of the patch 10 spaced from the first surface 16,the second sensor 26 may be spaced from the second surface 18 by adistance H. Spacing the second sensor 26 from the second surface 18 inthis way may assist in minimizing and/or eliminating inaccuracies intemperature measurements caused by, for example, ambient temperaturesand/or the temperature of the second surface 18. The system may inferthe cause of a temperature change to be internal (the patient) orexternal (ambient) by the causal relationship between detected changeson the first sensor 24 and second sensor 26. As an example, a feverspike would first sensor 24 to increase in temperature and then as theheat flux flows through the system, second sensor 26 would increaseslightly. In contrast, if the patient is below an air vent and hot airbegins to flow, then the second sensor 26 would heat without the firstsensor 24 first detecting a temperature increase. The system may adjustthe formulae and/or weightings used to calculate temperature based onthe magnitude and causal relationship between temperature readings. Thesystem may also time average readings or otherwise filter the raw sensordata to improve the temperature reading accuracy.

FIG. 4 illustrates the first surface 16 of an example patch 10 in whichat least a portion (e.g., the front surface 38) of the conductor 36extends substantially coplanar with and/or forms at least a portion ofthe first surface 16 of the patch 10. As shown in FIG. 4, in someexamples the conductor 36 may include a first side surface 47 extendingsubstantially perpendicular to the top surface 40 and/or the bottomsurface 42. Additionally, the conductor 36 may include a second sidesurface 49 opposite the first side surface 47. In such examples, thesecond side surface 49 may also extend substantially perpendicular tothe top surface 40 and/or the bottom surface 42, and may besubstantially parallel to the first side surface 47. In such examples,the conductor 36 may have a width I extending from the first sidesurface 47 to the second side surface 49. Patch 10 need not be aquadrilateral and need not be a regular polygon. It may have planarcross-sections, including but not limited to: an ellipse, rectangle,superellipse, pentagon, hexagon, parallelogram, trapezoid, and the like.

Additionally, as shown in FIG. 4 the patch 10 may further include afifth surface 48 substantially perpendicular to at least one of thefirst and third surfaces 16, 28 of the patch 10. The patch 10 may alsoinclude a sixth surface 50 opposite the fifth surface 48. In suchexamples, the sixth surface 50 may also be substantially perpendicularto at least one of the first and third surfaces 16, 28 of the patch 10,and may be substantially parallel to the fifth surface 48. Thus, thepatch 10 may have a width K extending from the fifth surface 48 to thesixth surface 50. In such examples, the first side surface 47 of theconductor 36 may be spaced from the fifth surface 48 of the patch 10 bya third distance ii, and the second side surface 49 of the conductor 36may be spaced from the sixth surface 50 of the patch 10 by a fourthdistance J₂. In some examples, the third and fourth distances J₁, J₂ maybe substantially equal to one another. Alternatively, in further exampleembodiments, the fourth distance J₂ may be different from the thirddistance J₁. Additionally, in example embodiments at least one of thefirst distance E₁ or the second distance E₂ may be substantially equalto at least one of the third distance ii or the fourth distance J₂. Inany of the example embodiments described herein, at least one of thefirst, second, third, or fourth distance E₁, E₂, J₁, J₂ may be betweenapproximately 0 mm and approximately 8 mm.

As described above with respect to the first and second distances E₁,E₂, collectively, the third and fourth distances J₁, J₂ may be referredto as a “pullback” of the patch 10, and in general, such a pullback maybe defined by the distance by which one or more surfaces or edges of theconductor 36 is spaced from one or more corresponding adjacent surfacesor edges of the patch 10. It is understood that by increasing thepullback of the patch 10 associated with the third and fourth distancesJ₁, J₂, inaccuracies in skin temperature measurement caused by, forexample, the relative coolness of the fifth and sixth surfaces 48, 50 ofthe patch 10 may be minimized. However, increasing the third and fourthdistances J₁, J₂ may also decrease the overall width I of the conductor36, and may result in an overall decrease in the surface area of thefront surface 38. Accordingly, in some examples, increasing the pullbackof the patch 10 associated with the third and fourth distances J₁, J₂may result in a patch 10 that is more susceptible to inaccuracies inskin temperature measurement caused by skin irregularities, air pocketsformed between the skin surface and the first surface 16 of the patch10, and/or other environmental factors associated with skin temperaturemeasurement.

As noted above, the position of the conductor 36 relative to varioussurfaces and/or portions of the patch 10 may have an effect on thetemperature determinations made by one or more of the sensors 24, 26described herein. As will be described below, the thickness A of theinsulator may have an effect on such temperature determinations. Thethickness C, height D, width I, size, material, and/or otherconfigurations of the conductor 36 may also have an effect on suchtemperature determinations. FIGS. 5 and 6 provide temperature plotsillustrating such effects.

For example, FIG. 5 is a temperature plot illustrating a series ofsample surface temperatures T_(s) measured with example patches 10including one or both of the first and second sensors 24, 26. Fortesting purposes, the temperature of the sample surface being measuredwas held constant at approximately 96° Fahrenheit. The example patches10 utilized to measure the temperatures T_(s) illustrated in FIG. 5 eachincluded an insulator with a thickness A of 5 mm and a conductor 36 withthickness 0.4 mm. Additionally, the example patches 10 includedpullbacks (associated with the first and second distances E₁, E₂,) of 0,2, 4, 5, 7, and 8 mm, respectively. As can be seen in the temperatureplot of FIG. 5, for patches 10 having conductors 36 with respectivethicknesses C of 5 mm, a pullback associated with the first and seconddistances E₁, E₂, of 5 mm resulted in a measured temperature T_(s) thatmost closely corresponded to the actual temperature of the samplesurface being measured.

FIG. 6 is another temperature plot illustrating a series of samplesurface temperatures T_(s) measured with example patches 10 includingone or both of the first and second sensors 24, 26. For testingpurposes, the temperature of the sample surface being measured was heldconstant at approximately 96° Fahrenheit. The example patches 10utilized to measure the temperatures T_(s) illustrated in FIG. 6 eachincluded an insulator with a thickness A of 3 mm and a conductor 36 withthickness 0.4 mm. Additionally, similar to the patches described abovewith respect to FIG. 5, the example patches 10 associated with thetemperature plot of FIG. 6 included pullbacks (associated with the firstand second distances E₁, E₂,) of 0, 2, 4, 5, 7, and 8 mm, respectively.As can be seen in the temperature plot of FIG. 6, for patches 10 havinginsulators with respective thicknesses A of 3 mm, a pullback associatedwith the first and second distances E₁, E₂, of 5 mm resulted in ameasured temperature T_(s) that most closely corresponded to the actualtemperature of the sample surface being measured. Physical factors ofthe amount of pull-back as well as the percentage of the surface coveredby the conductor 36 (e.g., 100%*(D*I/K*F) affect the fringing fields. Insome embodiments, example pullbacks described herein may decreasethermal coupling of the conductor to the ambient. In such examples, theconductor 36 may be substantially centered on the patch 10 for patches10 of size about 25 mm×25 mm. For relatively large patches 10, theconductor 36 could be offset from the center of the patch 10 and stillnot be near the edge. In example embodiments in which the patch 10 isrelatively small, the conductor 36 may also be relatively small and/orthe pullback may be relatively small. In the limit of no pullback(E₁=E₂=J₁=J₂=0) and in the limit of a D and I approaching 0 (approachingno conductor), there is decreased benefit of adding the conductor 36. Asa result, in some examples, relatively small patches 10 may benefit lessfrom the presence of the conductor 36. In the limit of a relativelylarge insulator, there may be little additional gain from making theconductor 36 large, so the pullback will tend to increase as the size ofthe patch 10 increases. A conductor 36 that is thicker in the middlethan the edges provides a method to have thermal mass and larger areawhile minimizing the edged effects because the thermal resistance of theedges is reduced due to the thinness of the conductor 36 in that region.The more perfect the adhesion between patch 10 and the subject, the lessthe fringing effect as the conductor 36 is better shielded from ambientconditions with better adhesion. Additionally, with this configuration,the thicker insulator (the insulator associated with the temperatureplot of FIG. 5 having a thickness A of 5 mm) generally resulted in moreaccurate temperature measurements (e.g., measured temperatures T_(s)close to the actual temperature of the sample surface). With a thickerinsulator there is less heat transfer from the subject to the exteriorenvironment (this environment includes the patch 10), so the systemtends to be closer to the subject temperature. The thinner insulatortends to have a longer thermal time constant. The system may be designedusing different thicknesses and sizes of insulators and with differentthicknesses and sizes of conductive material to optimize response timevs accuracy.

FIG. 7 illustrates an example system of the present disclosure. As shownin FIG. 7, such an example system may include at least one patch 10. Anexample system may also include a device 58, such as an RFID reader, ahand-held control device, and/or other noncontact sensing device. Such adevice 58 is illustrated in FIG. 7 as being a handheld device, carriedby a hand 60 of a user. Such devices 58 may be configured to providepower to at least one of the first and second sensors 24, 26 bydisposing the device 58 at a distance less than or equal to a minimumdistance L from the transmitter 32. Additionally, the transmitter 32 maybe configured to provide information indicative of respectivetemperatures determined by the first and second sensors 24, 26, and/orone or more sub-skull or other core temperature values determined by thecontroller 21, to the device 58 when the device 58 is disposed at adistance less than or equal to the distance L from the transmitter 32.In some examples, the distance L may be, for example, the sensitivityrange of the device 58 and/or the transmission range of the transmitter32.

As shown in FIG. 7, in some examples the patch 10 may be removablydisposed on the forehead 12 of a subject 14, and may be removablyattached to an outer surface 56 and/or other measurement site on thelayer of skin 54 covering the frontal skull bone 52. In such examples,the conductor 36 may be in contact with the outer surface 56 of thelayer of skin 54, thereby improving the transmission of heat from thesurface 56 to the conductor 36. Such intimate contact between theconductor 36 and the surface 56 may also increase the relativetemperature of the first sensor 24 configured to determine thetemperature of the conductor 36.

Additionally, such improved transmission of heat and/or increases in therelative temperature of the first sensor 24 may reduce and/or minimizethe dependence upon a correction factor when calculating a sub-skulltemperature and/or other core temperature of the subject 14. Reducingsuch dependence upon a correction factor for sub-skull and/or coretemperature value determinations may be beneficial in order to avoiderrors in the correction factor caused by, among other things,environmental factors such as variations in ambient temperature.Additionally, correction factors such as the ratio between a thermalresistance R_(s) of the layer of skin 54 and a thermal resistance R_(l)of the material 46 separating the first sensor 24 from the second sensor26 may have a certain level of inherent error notwithstanding othererrors that may be the result of environmental influences. Thus,reducing the dependence upon such correction factors may improve theaccuracy of the sub-skull temperature and/or other temperaturedeterminations made using the systems described herein.

FIGS. 8 and 9 include flowcharts illustrating various example methods ofthe present disclosure. For example, FIG. 8 includes a flowchart 100illustrating an example method of manufacturing a system of the presentdisclosure. As noted above with respect to FIG. 7, such a system mayinclude a patch 10, at least one sensor, a conductor 36, and/or anyother components described herein with respect to FIGS. 1-7.Additionally, such a system may include one or more noncontact sensingdevices 58 configured to communicate with and/or otherwise interact withthe patch 10 and/or components thereof. As shown in FIG. 8, at step 102such an example method of manufacturing may include providing a patch 10defining a first surface 16 and a second surface 18 opposite the firstsurface 16. As noted above, in some example embodiments the firstsurface 16 may be removably attachable to a surface 56 of a layer ofskin 54 of a subject 14, and/or to any other measurement site. Such anexample method may also include, at step 104, and connecting a conductor36 to the patch 10 at a location spaced from the second surface 18. Forexample, the conductor 36 may be disposed proximate the first surface 16so as to maximize the transmission of heat (e.g., a heat flow rate) fromthe surface 56 to the conductor 36 when the patch 10 is attached to thesurface 56. In some examples, step 104 may include positioning theconductor 36 such that the front surface 38 of the conductor 36 extendssubstantially coplanar with the first surface 16 of the patch 10. Insuch embodiments, the conductor 36 may form at least a portion of thefirst surface 16 of the patch 10. In additional examples, step 104 mayalso include positioning the conductor 36 such that the top surface 40of the conductor 36 is spaced from the third surface 28 of the patch 10by a first distance E₁. Step 104 may further include positioning theconductor 36 such that the bottom surface 42 of the conductor 36 isspaced from the fourth surface 30 of the patch 10 by a second distanceE₁ substantially equal to the first distance E₁. By spacing the top andbottom surfaces 40, 42 of the conductor 36 from the third and fourthsurfaces 28, 30, respectively, errors in temperature measurement causedby environmental influences such as, for example, ambient temperaturemay be minimized and/or substantially eliminated. For example, incircumstances in which the temperature of one or more sides, surfaces,edges, and/or other portions of the patch 10 is increased or decreaseddue to ambient temperature conditions, the effect of such increases ordecreases in temperature can be minimized by spacing surfaces and/orother portions of the conductor 36 from such portions of the patch 10.

Example methods of the present disclosure may also include, at step 106,operably connecting the first sensor 24 to the patch 10. In particular,the first sensor 24 may be configured to determine a temperature of theconductor 36, and in such examples, the first sensor 24 may beelectrically, mechanically, and/or otherwise operably connected to theconductor 36 in order to facilitate such temperature determinations. Forexample, the first sensor 24 may be operably connected to the conductor36 so as to determine the temperature of at least a portion of at leastone of the front surface 38 or the back surface 44. In exampleembodiments in which the first sensor 24 includes one or more sensingelements, each of the sensing elements may be operably connected to theconductor 36 at step 106.

The method may also include, at step 108, operably connecting the secondsensor 26 to the patch 10. For example, at step 108, the second sensor26 may be spaced from the first sensor 24 by material 46 having a knownthermal resistance. In some examples, the material 46 may comprise atleast a portion of the patch 10. Additionally, in such examples thesecond sensor 26 may be configured to determine at least one additionaltemperature associated with the patch 10. For example, whereas the firstsensor 24 may be positioned and/or otherwise configured to determine oneor more temperatures associated with the conductor 36, the second sensor26 may be positioned and/or otherwise configured to determine atemperature of at least a portion of the patch 10 spaced from theconductor 36. In such examples, such a portion of the patch 10 mayinclude the second surface 18 and/or or more portions of the patch 10proximate the second surface 18.

In example embodiments, a method of manufacturing may also include, atstep 110, electrically, mechanically, operably, and/or otherwiseconnecting the wireless transmitter 32 to the patch 10. In particular,step 110 may include, among other things, operably connecting thewireless transmitter 32 to at least one of the first and second sensors24, 26. In such examples, the wireless transmitter 32 may be configuredto wirelessly provide a first temperature, such as a temperature of atleast a portion of the conductor 36, determined by the first sensor 24to one or more noncontact sensing devices 58 such as via Bluetooth,radio transmission, Wi-Fi, and/or other communication means. Forexample, in some embodiments the wireless transmitter 32 may compriseone or more RFID coils configured to wirelessly provide information toan RFID reader or other noncontact sensing device 58 via radiotransmission. Wireless transmitter 32 may also be configured towirelessly provide an additional temperature determined by the secondsensor 26 to the device 58. In such examples, one or more processors,controllers, and/or other components of the device 58 may be configuredto determine one or more sub-skull temperatures or other such coretemperatures of the subject 14 based at least partly on at least one ofthe temperature of the conductor 36 determined by the first sensor 24 orthe additional temperature determined by the second sensor 26.

In still further examples, the wireless transmitter 32 may be configuredto wirelessly provide one or more sub-skull temperatures or other suchcore temperatures of the subject 14 to the noncontact sensing device 58.In such examples, such temperatures may be determined by one or morecontrollers 21 associated with the patch 10 based at least partly on atleast one of the temperature of the conductor 36 determined by the firstsensor 24 or the additional temperature determined by the second sensor26.

Accordingly, some example methods of manufacturing may also includeconnecting, at step 112, a controller 21 to the patch 10. For example,step 110 may include mounting the controller 21 within the patch 10 andoperably connecting at least one of the first sensor 24 or the secondsensor 26 to the controller 21. In such examples, the at least one ofthe first sensor 24 or the second sensor 26 may be configured totransmit determined temperatures and/or other information to thecontroller 21, and the controller 21 may be configured to calculate asub-skull temperature and/or other core temperature of the subject 14based on such temperatures. Additionally, as will be described infurther detail below, the controller 21 may be configured to calculate asub-skull temperature and/or other core temperature of the subject 14based at least partly on such temperatures and based on the thermalresistance of the material 46 spacing the first sensor 24 from thesecond sensor 26. In still further examples, such core temperaturedeterminations may also be made based on one or more additional inputs,such as a measured ambient temperature, an average temperature based ona plurality of patch temperature and/or skin surface 56 temperaturemeasurements, a blood oxygen concentration measurement, rate of changeof temperature of the first sensor 24 compared to the second sensor 26,causal relationship between temperature changes detected by the firstsensor 24 and the second sensor 26, air velocity detectors thatdetermine if heating and/or air conditioning breezes are present, and/orother measurements that improve the precision of the measurement.

FIG. 9 includes a flowchart 200 illustrating another example method ofthe present disclosure. In particular, the flow chart illustrates anexample method of determining a sub-skull and/or other core temperatureof the subject 14. As illustrated by FIG. 9, in an example embodiment asub-skull and/or other core temperature may be determined by sensing oneor more temperatures associated with the forehead skin 54 and/or of thepatch 10 while the patch 10 is at least temporarily contacting and/orremovably attached to the forehead 12. For example, in order tocalculate a sub-skull temperature, a temperature of the first surface 16and/or of the conductor 36 contacting the forehead 12 may be sensed,along with a temperature of another portion of the patch 10 spaced fromthe forehead 12. In additional example embodiments, such temperaturemeasurements may be taken at two different predetermined levels, depths,or locations within the patch 10, and along a heat transfer flow pathwithin the patch 10 (e.g. between the surface 56 and one or both of thesensors 24, 26). In such embodiments, the sensors 24, 26 may bepositioned at such predetermined locations within the patch 10 fortemperature measurement. According to basic heat transfer theory, thequantitative value of heat flow (q) is generally equal to the amount ofheat energy passing through a given system over time. Such heat flow isgoverned by the resistance of the system as well as the temperature dropacross the system. In the case of a subject 14, the sub-skulltemperature and/or other core temperature of the subject 14 can besolved for utilizing these heat flow relationships.

With reference to the flowchart 200 illustrated in FIG. 9, an examplemethod of the present disclosure may include removably attaching thepatch 10 to a skin surface 56 of the subject 14 at step 202. Forexample, the first surface 16 of the patch 10 may be at leasttemporarily adhered to the surface 56 of the forehead 12 and/or to anyother measurement site of the subject 14, such as an alternate skinsurface. At step 204, the wireless transmitter 32 of the patch 10 maywirelessly receive one or more activation signals from a remote device.For example, the wireless transmitter 32 may receive one or more controlsignals from one or more noncontact sensing devices 58, such as viaBluetooth®, radio transmission, Wi-Fi®, and/or other communicationmeans. As noted above, in some embodiments the wireless transmitter 32may comprise one or more RFID coils. In such embodiments, at step 202the wireless transmitter 32 may receive power from an RFID reader orother noncontact sensing device 58 when the device 58 is disposed at adistance less than or equal to the distance L described above withrespect to FIG. 7. Power and/or other activation signals received by thewireless transmitter 32 at step 204 may energize and/or otherwiseactivate components of the patch 10 operably connected to the wirelesstransmitter 32 including, for example, the controller 21, the firstsensor 24, and/or the second sensor 26.

For example, at step 206 the controller 21 may control and/or otherwisecause the first sensor 24 to determine a first temperature associatedwith the conductor 36. In particular, the activation signal received bythe wireless transmitter 32 at step 204 may cause the controller 21 toperform one or more functions, operations, and/or methods. Such methodsmay include, for example, directing one or more components of the patch10 to perform one or more temperature determinations. For example, atstep 206 the first sensor 24 may sense and/or otherwise determine atemperature of the conductor 36 in response to one or more controlsignals received from the controller 21. Such temperatures may include,for example, one or more temperatures of the front surface 38 of theconductor 36 disposed proximate and/or in contact with the skin surface56 of the subject 14. Additionally, at step 206 the first sensor 24 mayprovide one or more signals including information indicative of suchtemperatures to the controller 21 and/or to the wireless transmitter 32.

At step 208, the controller 21 may control and/or otherwise cause thesecond sensor 26 to determine an additional temperature associated withat least a portion of the patch 10 spaced from the conductor 36 and/orfrom the first surface 16 of the patch 10. In particular, the activationsignal received by the wireless transmitter 32 at step 204 may cause thecontroller 21 to direct the second sensor 26 to sense and/or otherwisedetermine such an additional temperature. The additional temperaturedetermined by the second sensor 26 in response to one or more controlsignals received from the controller 21 may include, for example, one ormore temperatures of a portion of the patch 10 proximate and/orincluding the second surface 18. Such additional temperatures may beapproximately equal to an ambient temperature in some situations.Additionally, at step 208 the second sensor 26 may provide one or moresignals including information indicative of such additional temperaturesto the controller 21 and/or to the wireless transmitter 32.

In some examples, such methods may also include calculating and/orotherwise determining, at step 210, a sub-skull temperature and/or othercore temperature of the subject 14 based at least partly on therespective temperatures determined by the first and second sensors 24,26. Such methods may also include providing, at step 212, informationdetermined by at least one of the first sensor 24, the second sensor 26,or the controller 21 to the noncontact sensing device 58. Suchinformation may include, for example, the respective temperaturesdetermined by the first and second sensors 24, 26 and/or the thermalresistance of the material 46 separating the first sensor 24 from thesecond sensor 26. In such examples, a controller, processor, and/orother component of the device 58 may determine a sub-skull temperatureand/or other core temperature of the subject 14 based at least partly onthe information provided at step 212.

In further embodiments, the information provided at step 212 may alsoinclude, for example, a sub-skull temperature and/or other coretemperature of the subject 14 determined by the controller 21 at step210. In such examples, the controller 21 of the patch 10 may receivesignals from the first and second sensors 24, 26 indicative ofrespective temperatures determined by the sensors 24, 26. The controller21 may determine, at step 210, a sub-skull temperature and/or other coretemperature of the subject 14 based at least partly on the informationreceived from the first and second sensors 24, 26 and/or the thermalresistance of the material 46 separating the first sensor 24 from thesecond sensor 26. At step 212, the controller 21 may wirelessly providethe sub-skull temperature and/or other core temperature of the subject14 to the device 58 via the wireless transmitter 32.

In each of the example embodiments described herein, the controller 21of the patch 10 and/or one or more processors, controllers, or othercomponents of the device 58 may calculate the amount of heat flowing outof the forehead 12, and thus the sub-skull temperature T_(sub-skull)and/or other core temperature of the subject 14, according to thefollowing equation:T _(sub-skull) =T ₁ +R(T ₁ −T ₂).

In the above equation, “T₁” may be the first temperature determined bythe first sensor 24 at step 206, and “T₂” may be the additionaltemperature determined by the second sensor 26 at step 208.Additionally, in the above equation “R” may be a constant that isestimated and/or empirically determined based upon the physicalcharacteristics of the subject 14 and/or the patch 10. In particular,the constant R may be a thermal resistance associated with the skullbone 52 and/or skin 54 of the forehead 12. In an example embodiment, theconstant R may represent the thermal resistance of the forehead 12consisting of both the skull bone 52 and skin 54. The value of theconstant R utilized in the sub-skull temperature and/or other coretemperature calculation may vary within a relatively limited range basedon one or more physical characteristics of the subject 14. For example,a range of constants R may be estimated and/or empirically determinedbased upon at least one of the age, weight, gender, and/or othercharacteristics of the subject 14, and the values of such constants Rmay have a variation on the order of approximately 20%. In determiningthe sub-skull and/or other core temperature of a particular subject 14,a constant R may be chosen based upon whether the subject 14 is a smallchild, an average-sized adult, a large adult, and/or an elderly adult.In addition, the chosen constant R may vary for males as opposed tofemales, in any of the above age ranges or categories.

The value of each constant R may also be based upon the thermalresistance of the patch 10, or at least a portion thereof. The thermalresistance of portions of the patch 10 may be dependent upon thephysical construction and/or thermal characteristics of the patch 10such as, for example, the materials used to form the patch 10 and/or theone or more thicknesses thereof. In an example embodiment, the constantR may comprise a correction factor that is calculated by dividing thethermal resistance of the forehead 12 by the thermal resistance of atleast a portion of the patch 10. For example, the constant R may beequal to the thermal resistance R_(s) of the layer of skin 54 divided bythe thermal resistance R_(l) of the material 46 separating the firstsensor 24 from the second sensor 26. In still further embodiments, theconstant R may be equal to a thermal resistance of the forehead 12(e.g., a combined thermal resistance of the skull bone 52 and the layerof skin 54) divided by the thermal resistance R_(l) of the material 46.In still further embodiments, the constant R may be equal to the thermalresistance of the system between the heat source (e.g., the brain) andthe insulator, including the thermal resistance of the skull, skin,thermal contact resistance between the skin and the patch 10 divided bythe thermal resistance R_(l), of the material 46. In exampleembodiments, the constant R may be determined through experimentationand/or through one or more clinical trials utilizing differentconstructions and/or embodiments of the patch 10 to measure and/orcalculate sub-skull temperatures and/or other core temperatures ofsubjects 14 having a variety of different ages, weights, genders, and/orother physical characteristics. A healthcare professional may determinewhich constant R to use for a given subject 14 and patch 10 using one ormore look-up tables or other resources.

In additional example embodiments, the sub-skull temperature and/orother core temperature of the subject 14 may be determined based on oneor more physical characteristics, conditions, and/or other metricsassociated with the subject 14 and indicative of blood flow. Forexample, in calculating such a sub-skull temperature, a healthcareprofessional may measure, determine, and/or otherwise sense a metricindicative of blood flow at the forehead skin 54 of the subject 14.Significant blood flow proximate the first surface 16 of the patch 10may cause error in temperature and/or other measurements obtained withthe patch 10. For these reasons, it may be desirable and/or advantageousto avoid positioning the patch 10 proximate the temporal artery, orother veins or arteries of the subject 14. The forehead 12 of thesubject 14 may be particularly well suited for calculating sub-skulltemperature and/or other core temperatures according to the examplemethods described herein because the forehead 12 is generally free fromsuch blood flow passageways. Accordingly, sensing a metric indicative ofblood flow at the forehead skin 54 may assist in minimizing and/orsubstantially illuminating error in the temperature calculation.

Example systems of the present disclosure may provide advantages overexisting temperature measurement devices and/or systems. For example,positioning the conductor 36 proximate, adjacent to, and/orsubstantially coplanar with the first surface 16 of the patch 10 maymaximize the heat transfer between the skin surface 54 and the variouscomponents of the patch 10. Increasing the surface area of at least thefront surface 38 of the conductor 36 in communication with the skinsurface 54 may further improve the heat transfer characteristics of thepatch 10. Additionally, spacing the top and bottom surfaces 40, 42 ofthe conductor 36 from the third and fourth surfaces 28, 30 of the patch10, respectively, may minimize and/or substantially eliminatetemperature measurement errors caused by ambient and/or otherenvironmental conditions. As described herein, the thickness C, heightD, width I, and/or other characteristics of the conductor 36 may betuned in accordance with the considerations and techniques discussedabove in order to maximize the accuracy of temperature measurements madeusing the patch 10. The effects of each of these characteristics maycontribute to the overall accuracy of such measurements. Moreover, thewireless transmitter 32, controller 21, and/or other components of thepatch 10 may receive power from and may wirelessly communicate with thenoncontact sensing device 58. Such wireless power transfer andcommunication may facilitate substantially nonintrusive monitoring ofthe subject 14, and as a result, may improve patient comfort inhealthcare settings, provide early detection of febrile spikes therebyalerting clinicians of a need to attend to the patient, decrease thetime it takes to measure routine vital signs, and decrease the time inthe hospital. At home, use of the various systems described hereinallows parents peace of mind as the system automatically measures andreports temperatures, alerting the parents when a sick child'stemperature reaches a critical level.

The invention has been described in detail with particular reference toa presently preferred embodiment, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention. The presently disclosed embodiments are, therefore,considered in all respects to be illustrative and not restrictive. Thescope of the invention is indicated by the appended claims, and allchanges that come within the meaning and range of equivalents thereofare intended to be embraced therein.

What is claimed is:
 1. A system, comprising: a patch defining a firstsurface and a second surface opposite the first surface, wherein thefirst surface is removably attachable to skin of a subject, the patchcomprising: a conductor associated with the first surface, a firstsensor configured to determine a temperature of the conductor, a secondsensor configured to determine an additional temperature, wherein thefirst sensor is separated from the second sensor by a material having afirst thermal resistance, an RFID antenna operably connected to thefirst sensor and the second sensor, wherein the RFID antenna isconfigured to provide at least one of the temperature of the conductor,the additional temperature, or a core temperature of the subject to anRFID reader; and a controller operably connected to the first sensor,the second sensor, and the RFID antenna, the controller being configuredto: activate using power received via the RFID antenna, cause powerprovided via the RFID antenna to be directed to the first sensor and thesecond sensor, and determine, using the power received via the RFIDantenna, the core temperature of the subject based on the temperature ofthe conductor, the additional temperature, and the first thermalresistance of the material.
 2. The system of claim 1, wherein the patchcomprises an additional material having a second thermal resistance, andthe second thermal resistance is different from the first thermalresistance.
 3. The system of claim 1, the patch further comprising athird surface substantially perpendicular to the first surface, and afourth surface opposite the third surface, the patch having a thicknessextending from the first surface to the second surface, and a heightextending from the third surface to the fourth surface, wherein: theconductor extends substantially parallel to the second surface, andsubstantially perpendicular to at least one of the third surface or thefourth surface.
 4. The system of claim 3, wherein the conductor includesa top surface spaced from the third surface by a first distance, and abottom surface opposite the top surface and spaced from the fourthsurface by a second distance substantially equal to the first distance.5. The system of claim 4, the patch further comprising a fifth surfacesubstantially perpendicular to the first and third surfaces, and a sixthsurface opposite the fifth surface, the patch having a width extendingfrom the fifth surface to the sixth surface, wherein the conductorincludes a first side surface spaced from the fifth surface by a thirddistance, and a second side surface opposite the first side surface andspaced from the sixth surface by a fourth distance substantially equalto the third distance.
 6. The system of claim 5, wherein at least one ofthe first distance or the third distance is between approximately 0 mmand approximately 8 mm.
 7. The system of claim 5, wherein the firstdistance is substantially equal to the third distance.
 8. The system ofclaim 1, wherein the conductor includes a front surface spaced from thefirst surface by at least a portion of the patch.
 9. The system of claim1, wherein the conductor includes a front surface extendingsubstantially coplanar with the first surface.
 10. The system of claim1, wherein the first sensor comprises a plurality of sensing elementsconfigured to determine respective temperatures of a front surface ofthe conductor, the front surface being disposed adjacent to the firstsurface of the patch, and the controller being configured to determinethe temperature of the conductor based on the respective temperatures.11. The system of claim 10, wherein the temperature of the conductorcomprises an average of the respective temperatures.
 12. The system ofclaim 1, wherein the material is separate from and embedded within thepatch, the material separating the first sensor from the second sensor.13. The system of claim 12, wherein: the first thermal resistance isdifferent from a second thermal resistance of the patch, and the firstsensor is disposed between the material and the conductor.
 14. A system,comprising: a patch defining a first surface and a second surfaceopposite the first surface, wherein the first surface is removablyattachable to skin of a subject, the patch comprising: a conductorassociated with the first surface, a first thermistor configured todetermine a temperature of the conductor, a second thermistor configuredto determine an additional temperature, wherein the first thermistor isseparated from the second thermistor by a material having a firstthermal resistance, a transmitter operably connected to the firstthermistor and the second thermistor, wherein the transmitter isconfigured to wirelessly provide at least one of the temperature of theconductor, the additional temperature, or a core temperature of thesubject to a device separate from the patch; and a controller operablyconnected to the first thermistor, the second thermistor, and thetransmitter, the controller being configured to: activate using powerreceived wirelessly via the transmitter, cause power provided via thetransmitter to be directed to the first thermistor and the secondthermistor, and determine, using the power received wirelessly via thetransmitter, the core temperature of the subject based on thetemperature of the conductor, the additional temperature, and the firstthermal resistance of the material.
 15. The system of claim 14, whereinthe transmitter is configured to provide power to at least one of thefirst thermistor and the second thermistor.
 16. The system of claim 14,wherein the conductor comprises one of a metallic sheet or anelectrically conductive gel.
 17. The device of claim 14, wherein theconductor includes a front surface extending substantially parallel tothe second surface, a back surface opposite the front surface, and athickness extending from the front surface to the back surface, whereinthe thickness is between approximately 0.001 mm and approximately 5 mm.18. The system of claim 17, wherein the front surface extendssubstantially coplanar with the first surface.
 19. The system of claim14, the patch further comprising: a third surface substantiallyperpendicular to the first surface, a fourth surface opposite the thirdsurface, a fifth surface substantially perpendicular to the first andthird surfaces, and a sixth surface opposite the fifth surface, whereinthe conductor includes: a top surface spaced from the third surface by afirst distance, a bottom surface opposite the top surface and spacedfrom the fourth surface by a second distance substantially equal to thefirst distance, a first side surface spaced from the fifth surface by athird distance, and a second side surface opposite the first sidesurface and spaced from the sixth surface by a fourth distancesubstantially equal to the third distance.